How it works
Loop resistance=2×resistivity×one-way length/area; voltage drop=current×resistance; wire loss=current²×resistance.
Input definitions
- Source voltage (V)
- Enter the value in the labeled unit.
- Current (A)
- Enter the value in the labeled unit.
- One-way wire length (m)
- Enter the value in the labeled unit.
- Wire cross-section (mm²)
- Enter the value in the labeled unit.
- Resistivity at operating temperature (Ω·mm²/m)
- Enter the value in the labeled unit.
A worked example
- Source voltage (V)
- 12
- Current (A)
- 10
- One-way wire length (m)
- 10
- Wire cross-section (mm²)
- 2.5
- Resistivity at operating temperature (Ω·mm²/m)
- 0.0175
Assumptions & limits
Two-wire DC resistive calculation. Excludes AC reactance, joints, skin effect and automatic temperature correction. Not an installation design or legal cable-sizing assessment.
Sources & review
Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.
Method updated 2026-10-17. Content checked against the stated method and examples. Our verification approach.
Common questions
Does this replace a circuit or electrical safety assessment?
No. The result uses the idealized model shown. Component tolerance, temperature, fault conditions and installation requirements need separate evaluation.
How does the DC two-wire voltage drop tool work?
Loop resistance=2×resistivity×one-way length/area; voltage drop=current×resistance; wire loss=current²×resistance.
What are the assumptions and limits of DC two-wire voltage drop?
Two-wire DC resistive calculation. Excludes AC reactance, joints, skin effect and automatic temperature correction. Not an installation design or legal cable-sizing assessment.